Power unit for traveling cranes



Sept.,3, 1946. G. A; MITCHELL 2,406,889

V POWER UNIT FOR TRVELING CRANES Filed nec. 14; 1942 Patented Sept. 3, 1946 2,4o`sfss9 POWER UNrr Fon TRAVELING cRANEs George A. Mitchell, Muskegon, Mich., assignor to Manning, Maxwell & Moore, Inc., Muskegon, Mich., a corporation of New Jersey Application December 14, 1942, Serial No. 469,017

8 Claims.

The invention relates to driving mechanism for traveling bridge cranes or the like and more particularly to a power unit adapted for converting existing manually driven cranes for power operation.

One object of the invention is to provide novel means for mounting the power unit to the crane structure so that the shock andjar incident to the starting of the motor is effectually absorbed thus insuring smooth, shockless acceleration of the crane.

Another object is to provide a power unit for traveling bridge cranes and the like which is simple and compact in construction, inexpensive to manufacture, and which can be easily and conveniently installed in existing hand operated cranes to convert them for poweroperation.

Other objects and advantages l of 4the invention will become apparent from the following detailed description of the 'preferred embodiment illustrated in the accompanying drawing in which:

Figure 1 is a perspective view of a traveling4 bridge crane equipped with a power unit embody-A ing the features of the invention.

Fig. 2 is a fragmentary endelevational vie of the power unit.

Fig. 3'is a vertical sectional vie'w of the unit taken substantially on the line 33 of Fig. 2.

Referring to the drawing, the invention has been shown for purposes of illustration as applied to a traveling bridge crane having a bridge member in the form of an I-beam 5 supported at opposite ends by end trucks 6. Each end truck comprises an elongated frame 1 disposed transversely of the bridge member and clamped or otherwise rigidly attached to the bottom flange thereof. Flanged Wheels 8 and 9 journaled on trucks on opposite sides of the bridge member support the crane assembly on an overhead track formed by conventional rails IIJ.

Cranes of the above general character, as well as other types of cranes, hoists and various material handling devices, are commonly equipped with manually operable means for'traversing the crane structure or device on thesupporting track. In the exemplary bridge crane, this means comprises a horizontally disposed traverse drive shaft I I extending generally parallel to the bridge member 5 and journaled at opposite ends on the trucks 6. The shaft is drivingly connected with one wheel of each truck, as for example, the wheel 8, by means of pinions I2 fast on the shaft and arranged to meshwith gears I3 rigid with the corresponding wheels 8of therespec- (Cl. 10S-163) tive trucks. Rotation is imparted to the drive shaft by means of an endless chain running over a chain pocket wheel I4 xed on the shaft. The chain, of course, depends belows the crane structure to permit convenient hand manipulation by an operator standing on the floor.

The power unit comprising the present invention is particularly adapted for converting manually driven traveling bridge cranes of the type above discussed for power operation. In its preferred form, the unit comprises a rigid frame structure adapted to be suspended from the traverse drive shaft II and having driving means such as a chain pocket sheave 2| drivingly connected as by a chain 22 with the hand chain wheel I4 on the traverse shaft. A reversible motor M comprising an element of the unit isarranged to` drive the sheave 2I in any suitable manner.`

The motor` Mand other elements of the unit are supported in a compact assembly on the frame which is constructed to provide suitable housings for the moving partsand for the electrical equipment associated with `the motor. As herein shown a gear housing 24 is formed by a vertical frame member 25 (Figs. 2 and 3) of generally oval contour having an integral ange 26 extending around one side to define a relatively shallow vertically disposed gear compartment 21. This compartment is adapted to be closed by acover 28 bolted or otherwise rigidly secured to the anged member.

Projecting laterally from the frame member 25 on the side opposite the flange 26 and preferably substantially at right angles to the plane of the member is a rigid horizontal frame member or arm 2S terminating at its outer end in a box-like housing structure 30. A control relay :Ror other control mechanism for. governing the 'the'control of the motor is effected through the medium of a pendant switch (not shown) or other manuallyoperable circuit controlling device conveniently accessible to the operator of the crane,

. such manual device acting through the medium of the relay R to open and close the current "member 25 and spaced therefrom to provide clearance for the sheave 2|.V A boss 32 integral with the wall portion 3l is recessed to receive a bearing 33 in which is journaled one end of a shaft 34 adapted to support the sheave 2| and to which 3 the sheave is keyed. The other end of the shaft 34 is arranged to project into the housing 24 through an aperture in a boss 35 on the member 25 and is supported therein by a suitable bearing 3%. The housing 38 is dimensioned so that its top wall lies substantially in the same plane as the top of the housing 24 While its bottom Wall is located in a plane approximately through the center of the housing 24. Space is thus provided below the housing 30 for the motor M Which is preferably mounted directly on the fra-me member 25 with its .shaft ,MLproject-v ing into the housing 24. Suitablepackingisiprofvided around the motor shaftandthe shaft134`l:

to prevent leakage of oil or other lubricant around these parts.

The means for drivingly connectingthe-moton cludes av pinion 4l keyed tto the motor shaft 4- and arranged toA drivey an idler gear 4l2carriedf ona shaft l'journaled'at'oppositeends-on the frame member zi'andgthe cover- 28: Idler gear Erin-turn4 drives a gear M'keyed tothe inner end ofthe shaft Btonrwhich the` sheave 2l"is mounted;

Thel vertical arrangement of. thje housing` 2i" together ,with its shape conformingy Y generally to the progressively increasing diameters of` the pinions and `gears of the reduction, gear traingis Y advantageous inV reducing both theVV sizel and,`

weight of-'the framestructure toga minimurm Moreevel; the z arranaementnffthe, housing 30' and'themotor Mjat onerside of tlrehousingiM- andorre; above the other, providesra, @very compact'well' balanced `structure whichv can be `supportedin suspended relatio'ngfrom then drive shaft II^Without,'interferingqwiththe normal Yusemof the crane` andrwithout, imposing excessive strain on the shaft.

Any, suitable means` may* be utilized"for,sup-Y porting the unitjon the shaftdl in a manner, suehthatthev shafts-is free tojvturnnrelative Ato` the unit; As herein shown, the -supporting means comprisesfa pair of hangers 53 anchored to the' frame andyspaced apartv so as to straddle: thel handrhain Wheel I e as -shovvnrin Fig; 3: Eachf hanger preferably comprises-a yoke`5l havinga cap member '52 A'detachably secured to; its ,upper endi- Theyoke and -cap -memberare formed With4 complementary recesses adapted to hold a generallycylinclrical bearingmember 5-3 *dimensionedj' for -a rotating itwith Atheeshafi'fl I The -yokesV El of the hangers aresecured ,to the frame-by hangerl rods-54j threaded into bosses formedrespectively in the top-vvalls of Ithehousings -ZlthandD-Lof the frame. Toenable the unit to be properly positioned for/use Withhand chain Wheels of different diameters, the-yokesv ared 4 ated with the yoke and the other with the cap member. The parts can thus be separated for convenient application to the traverse drive shaft Without requiring any dismantling of the crane structure.

In order to make the unit universally applicable to the different sizes and types of cranes and comparable chain drivenl devices,v the hangers 50 and their bearing members 53 are separably assembled. More particularly, the half bushings forming the bearing members are loosely mounted,in.therecesses in yoke and cap member and are adapted toberetained in place after assemblyby fiangesv53 on the ends of the bushings., Inpracticaan assortment of interchangeable bearing members, all having the same outsidedimensionsI but varying in their internal dimensions to cooperate with shafts of different diameters will be kept in stock so that a bearing of the proper size may be selected for any* particularv installation'-` The chain 22 runningover the sheave^2lland hand chain wheel l kprovides; a` driving,A connec: tion whereby the torque of motor M may be transf mitted to the shaft Il.v With the ,unit thus supported on the traverse-drive. shaft, the torque appliedto the Wheel I4 Will'tendjto Vswing the .unit around the shaft. Due to the mounting, of the motor MJ and other heavy parts of theunit a; substantial distance below the axis of the shaft), the Weight of the unit isvdistributedlin a manner such as to oppose suchrotation.

Means is alsoprovided 'for yieldably,resisting bodilyrotation ofthe unitrelative to.tli'esup porting shaft an'dgfor absorbingtheshock and,- jar incident to; thestarting, ofr the.motort so.as

to insure smooth; 4shackles.; acceleration Aof,.the crane or device isolbernove.v The.,meanse1n ployedfor this purpose, asherein. shownicomprises a rigidban liavingopposite endfportions.vv

oiset with respect to each other but substantially parallel. Onevrendof, the bar iss/,secured :toastertionary .part of thecrane structure, as fora example, the bridgememberz. or-rI-beam: vv-hileathay other end is yieldablyranchored,tothe framefoftthe unit. Due to the offset relation .ofethesendpor-f tions, the bar mayl ,bel freadily.adjusted.rV for use with beams;y orwgirderst oi .various @depths-byyturna' ingy it ,through an angle sufficient;r to -zprovideithe necessaryfvertical spacing,;betWeen-fthefend rpolnf tions,.

While: anygsuitabletmeans mayzbeiutilzeaifomsecuring v the bar in `place,\it s preferable .tovclamppy the-.parto the,bridgelmemberfsdasetdavoiddrills neeor- Otherfmachne, nperationsfongthelmembery:

Theflampllglmeansa asiherein slinvyn,ecornprisesrf a pair-of QDlQQSed Clamping; devices :eachlincludingh a base,.,plate 6L having aitransversecentrallyfdis'-i posed sleeveip ortiorr Gbadaptedato'slidahin-receive 1' the bar SG. Adjustably securedfto `the-base plate;- asby bolts- 53,12 is .ai clam-ping plate 164:' havingJ its innerVK lowercedgegrecessed :to `extend-over .and co'-L operatewith',the-l ange oftheI-lloe'eam-as-shownL the `clamping,'.meansmay-belappliedstotthempper flangeuofgthe .beam if desired#- The clampingg devices may be-variably` jposi'# tioned and" locked in place'ion-cooperatiom with` I-beam-anges of different Widths:N Suehjposi* tioning Aand -locking- -iseffected#by-meansof vnuts 65 #threadedon jthe" bar--6|LJ and-positioned, to,l

engage-opposite ends of"the^sle'eve62. With the'.

clamping devices properlyjpositioned the clamp? ing plates maybe forced into'clamping engage-A ,ment with the lflange of the beam by tightening y the bolts 63.

' The other end of the anchoring bar ,65 is ladapted to be yieldably connected to the frame of the unit so as to permit limited rotation of the -unit relative to'theshaft in either direction. In the exemplary form disclosed thebar projects through an aperture in a lug 66 integral with the cover plate 28 and projecting laterally therefrom. The yieldable connection between the bar "and the lug is provided by a pair of coiled compression springs 61 and 68 encircling the bar and interposed between the lug and stationary members fixed to the bar on opposite sides of the lug. ThuS, spring 61 bears against a collar or washer BQ mounted on the bar and held against endwisc movement thereon by a` pin 10. Thespring 6B bears against a similar collar or washer 1l on the other end ofthe rod which is held against movement by a nut 12.

When the motor M is started to run in either direction the torque applied to the Wheel I4 tends to rotate the unit as a whole, thus compressing one or the other of the springs tl and 6B. The

resistance to such compression increases progressively so that the motor torque is applied gradually to the shaftV Il to accelerate the -crane smoothly and with complete absence of shock. The use of rheostats or comparable speed controllers is thus unnecessary and smooth starting ofthe crane is insured at all times. Moreover, the motor M may be of a relatively inexpensive single speed type which materially reduces the cost of the unit.

It will be apparent from the foregoing that the invention provides a power unit of novel and advantageous construction by which a wide variety of manually operated traveling bridge cranes and comparable chain driven devicesmay be readily converted for power operation. The unit is simple and compact and interferes in no way with the normal operation of the crane. By reason of the novel mounting of the unit and the means provided for absorbing the shock and jar incident to the starting of the driving motor, smooth, shockless acceleration of the crane is obtained even though a simple, inexpensive single speed motor is employed and complicated expensive starting equipment such as rheostats and the like are dispensed with. Thus, the unit is relatively inexpensive and yet capable of efficient operation in driving bridge cranes and the like. Due to the simple 'manner in which the unit is applied, it may be installed on existing cranes by relatively unskilled labor and withoutY requiring any modifications or changes in the crane structure and, in fact,V without drilling or other machine operations. Y

I claim as my invention:

l. A power unit for a traveling bridge crane or the like having a horizontally disposed transverse drive shaft with a hand chain wheel fast thereon, said unit comprising a rigid frame structure, hangers anchored to said frame structure in spaced relation each including a bearing element engageable with the drive shaft on opposite sides of the chain Wheel and operative -to Wsupport the unit on the shaft, a shaft journaled on said frame structure, a sheave fast on said last mentioned shaft, an endless driving chain connecting said sheave with said wheel, a motor secured to said frame structure, and means drivingly connecting said motor with the shaft carrying said sheave.

2. A power unit for a traveling crane or the.

like Vof the `type having a traverse drive shaft,

`said unit comprising, in combination, aframe ings, a motor secured to the sidewall of said iirst housing below said 4frame member, speed reduc.- tiongearing enclosed within said first housing drivingly connecting said motor with said shaft, means for supporting said frame on the traverse drive shaft of the crane, and means for drivingly connecting 'said sheave with the traverse drive shaft. 1

3. A power unit for a traveling crane or the like having a, horizontally disposed traverse drive shaft, said unit comprising, in combination, a `frame structure including members defining a pair of housings, a horizontal member rigidly connecting said housings, a shaft journaled in the respective housings, a sheavexed to said shaft intermediate the housings, a motor carried on one ofY said housings, speed reduction gearing enclosed in said onehousing drivingly' connecting said motor with the sheave carrying shaft, control means enclosed in the other of said housings for controlling the operation of said motor, a hanger anchored to each of said housings, said hangers having bearing elements shaft intermediate the housings, a motor carried' on one of said housings, speed reduction gearing enclosed in said one housing drivingly connecting said motor with the sheave carrying shaft, control means enclosed in the other of said housings for controlling the operation of said motor, a hanger anchored to each of said housings, said hangers having bearing elements engageable with the drive shaft of the crane to support the frame structure thereon, and a exible member drivingly connecting said sheave with the drive shaft, said hangers being adjustable to regulate the tension of said flexible member.

5. A power unit for a traveling crane or the like having a horizontally disposed transverse drive shaft, said u-nit comprising, in combinaation, a vertically disposed frame member, a iiange around the edge of said member projecting from one side thereof to dene a relatively shallow housing, a horizontally disposed frame member projecting from the other side of said vertical member, means forming a second housing integral with said horizontal member, said second housing being spaced laterally of said first housing, a shaft journaled on said housings and having a sheave xed thereon intermediate the housings, a motor secured to said vertical frame member below said horizontal frame member, speed reduction gearing in said iirst mentioned housing drivingly connecting said motor with the sheave carrying shaft, motor controlling means in'said second housing, .meansattached tosaid housings-for supporting the frame structure on'the traverse shaft of 'thecranef and meaHsdriVingIy connecting said sheave withv the traverse shaft.

6. A power unit `for la traveling crane or-the like having a horizontally ydisposed drive shaft, said unit comprising, -in `combination, va frame structure including V-a pai-r of laterally -spaced frame members, a horizontal member rigidly connecting said frame members, ashaft, -a sheave fixed to said shaft, bearings Acarried by/saidv frame members positioned to support said shaft on opposite sides of said sheave, a Amotor'mounted on one of said framemembers, speed reduction gearing connecting said motor-with said shaft, means cooperating with said one frame-member toform a'housing enclosing said gearing, other bearings engageable with the drive shaft of the crane to support said frame structure thereon, a flexible member drivingiy connecting said sheave with the drive shaft -of thecrane, and means connecting-said Iother .bearings to the respective frame members for-adjustment toward and from the members to regulate the tension vof said flexible member.

'7. A power unit for atraveling crane or the like having atraverse drive shaft, said unit comprising, in combination, a frame structure including a pair of laterally spaced rigidly connectedv members, a drive shaft jour-naled at opposite ends in said members and adapted to be drivingly connected with the traverse shaft, `a motor supported on one of said members, speed reduction gearing carried by one of said members for connecting said motor with said drive shaft, and means rigid with said frame structure for supporting it in suspended relationL to said traverse shaft, said supporting means being adjustable to vary the spacing of said .drive shaft from the traverse shaft.

8. The combination with a power unit adapted to be mounted in suspended relation from the traverse drive shaft of a traveling crane having a anged bridge member, of a torque arm connecting between said unit and the bridge member comprising a generally crank-shaped bar including a pair of parallel oppositely facing end sections and a central section angularly disposed with respect to said end sections, means yieldably connecting one end section of said arm with said Iunit at Va point spaced substantially from its point of suspension, and clamping means connecting the other end section of said arm with the flange of the bridge member, said clamping means being adjustable longitudinally of the bridge member and said arm being rotatable relative to the clamping means and to said unit so as to hold said unit in an upright position irrespective of the depth of the bridge member.

GEORGE A. MITCHELL. 

